Movement for heat exchange assembly



Jan'. 15, 1963v A, BRlDwELL ErAL 3,073,172

MOVEMENT FOR HEAT EXCHANGE ASSEMBLY Filed Dec. 9, i958 Sheets-Sheet 1 Jan. 15, 1963 R. A. BRlDwELL ETAL 3,073,172

MOVEMENT FOR HEAT EXCHANGE ASSEMBLY Filed Dec. 9, 1958 2 Sheets-Sheet 2 i ,i i i i 3,073,172 Patented Jan'. 15, 1953 United States arent dice 3,073,172 MOVEMENT FOR HEAT EXCHANGE ASSERBLY Robert A. Bridwell, Lynwood, and John H. Hanson, Los Angeles, Calif., assignors to lNorthrop Corporation, a corporation of California Filed Dec. 9, 1958, Ser. No. 779,243 Claims. (Cl. 74-110) This invention pertains to equipment adapted to facilitate the movement of a heat exchange or like assembly between two positions and more particularly to equipment adapted to facilitate and expedite the movement of a heat exchange assembly to and from a juxtaposed position with respect to a metal sheet, the sheet having been previously positioned in a forming position in a forming facility, whereby the temperature of the sheet may be elevated to a desired temperature and subsequently shaped without further movement of the sheet.

l It is a prerequisite of certain types of 'material that they must be heated prior to their fabrication. This is particularly true oftitanium and magnesium sheets, etc., and alloys thereof if they are to be effectively fabricated into sheet metal parts by stamping, pressing, drawing, and like operations. These blanks must be worked at elevated temperatures to render them suiiciently ductile to eliminate the occurrence of cracks, tears, and the like which normally occur during the working of these materials at ordina-ry room temperatures. Elevated temperatures as used throughout the specilication refer to temperatures in the 30G-1500 F. range.

It is well known in the metal working art that an elongation loss of approximately 66% is experienced in the forming of titanium, magnesium and like sheets should their temperature drop 200 from a maximum allowable temperature of approximately 900-l300 F. It, therefore, is apparent that sheet material of this type must be worked at a temperature as near as possible to the maximum allowable temperatureA to which such sheets are heated for optimum results.

To the best of applicants knowledge blank sheet material as described above are at present heated in an oven located in the immediate vicinity of a forming facility. However, this method is not satisfactory due to the time lag which necessarily occurs between the removal of a blank from an oven and an actual forming operation. A time lag of l2f-l5 seconds is required to remove the blank from an oven and place it in a forming facility during which time the blank experiences a temperature drop of as muchas 250 and a corresponding loss in elongation.

Accordingly it is an object of the present invention to disclose a facility making possible the heating of metal sheets to desired elevated temperatures and subsequently allows-them to be shaped at or near the elevated temperatures.

Another object is `to disclose a facility for heating metal sheets in which the elapsed time occurring between a heating and a forming operation thereon is minimized.

Another object is to disclose a facility for heating metal sheets in which the oxidation thereof is minimized. A

' Another object is to provide apparatus which facilitates and expedites the positioning of a heat source in a juxtaposed position with respect to a sheet metal blank while in its forming position in a forming facility and also facilitates and expedites Vthe removal of the heat source from the juxtaposed position referred to above.

"Although the characteristic features of the present invention are particularly pointed out in the appended claims, the invention itself, also the manner in which it may be carried out, will be better understood by referring to the following description taken in connection with the and in which:

FIGURE l is a sectional view of heating apparatus which may -be used in carrying out the process disclosed herein, the section being taken along the line 1 1 of FIGURE 2.

FIGURE 2 is a sectional View of the heating apparatus of FIGURE l as viewed along the line 2-2 of the latter ligure.

FIGURE 3 is a view of the heating apparatus similar to that shown in FIGURE 2 except the linkage assembly is shown in its retracted position.A

This invention utilizes a radiant heat source for the heating of titanium, magnesium and like sheet meal blanks which subsequently are to be formed into sheet metal parts. The blank sheets are first coated with a high temperature drawing compound so that they will absorb heat more readily.

The blanks are then positioned in their exact forming attitude in a 'forming facility. The aforementioned radiant heat source comprises a plurality of tube type radiant heaters mounted in a suitable reector, the number of heater tubes depending upon the size of the blanks to be heated. The reflector and heater tubes are now juxtapositioned above the 4blank so that the rays from the heater tubes are directed on the subject blank. The heater tubes are now energized and remain energized until such time as the temperature of the subject blank reaches a predetermined temperature. The reflector and heater tubes are then withdrawn from their juxtapositioned position above the blank allowing the forming operation to be effected without delay and with a minimum temperature loss.

Apparatus which may be utilized for positioning the radiant heat source in and subsequently removing it from the forming facility is shown in FIGURES 1-3. This apparatus, indicated in its entirety by the numeral 11, includes a wheeled enclosure 12, a scissor-type linkage assembly 14 and a reflector 16. I

The enclosure 12 is of box-like construction having upper, lower, fore, aft and side walls 17-22, respectively. All` of the walls are solid with the exception of the forward wall 19 which has an opening 23 formed therein and through which a portion of the linkage assembly and reflector passes in moving between the ref tracted and extended positions of the linkage assembly. The enclosure 12 is rendered mobile by wheel assemblies 24.

The linkage assembly 14 includes fore and aft subassemblies 26 and 27, respectively, which are of rectangular conguration, when viewed in plan as shown in FIG- URE l, and are constructed of tubular members. The fore and aft ends of the subassemblies 27 and 26, respectively, are pivotally mounted on an intermediate shaft 28. Also pivotally mounted on the shaft 28, at approximately the midpoint thereof, is a minor sheave 29 having a pair of spaced cable receiving grooves formed therein. The sheave 29 is iixedly secured to the forward yassembly 26 by a pair of brace members 31-31, accordingly the sheave 29 and the subassembly 26 move as a unit and the latter pivots on the shaft 28 to allow relative movement therebetween and the aft subassembly 27.

Mounted for rotational movement at the forward end of the subassembly 26 is a shaft 32 hereinafter referred to as the forward shaft. Fixedly secured to the forward -shaft 32 as by pins, keys or the like is the aforementioned reflector 16. Accordingly angular movement of the forward shaft 32 will be imparted to the reflector 16. A shaft 33, hereinafter referred to as the aft shaft, is rotatably mounted in the aft end of the subassembly 27. Also rotatably mounted on the aft shaft 33 is a major sheave 34 in which a single cable receiving groove is formed.

With the linkage assembly 14 in its extended position,

as shown in FIGURE 2, the midportion of a cable 36 is positioned in the aft portion of the groove formed in the major sheave 34 and is secured to the sheave in a conventional manner at a single point adjacent its midpoint. The free ends of the cable 36 are respectively positioned in the grooves in the minor sheave 29 and their extreme ends only are secured to the minor sheave 29 at positions as indicated at A and B in FIGURE 2. Cable tightening means 37 may be provided in the cable 36, and other cables to be described later, if desired.

Due to the size of the major sheave 34 with respect to the minor sheave 29 (diametrical ratio 2 to l) it will now be apparent that one quarter turn (90) of the subassembly 27 with respect to the sheave 34 will result in one half turn (180) of the minor sheave 29. This ratio and result are essential if the linkage assembly 14 is to function as intended as will be apparent as the disclosure progresses.

The reflector 16 comprises no part of the present invention and, therefore, is not described in detailin this application. However, the reector does include a plurality of tube-like radiant heaters 40 the axes of which are located in a common plane which has a parallel relation with respect to the top surface 38 of the reflector 16.

The linkage assembly 14 is completed by fore, aft and intermediate sheaves 39, 41 and 42 which are mounted on ends of the shafts 32, 33 and 28, respectively, which extend beyond one of the side edges of subassemblies 26 and 27. The fore and aft sheaves 39 and 41 have a single cable receiving groove formed therein while the intermediate sheave 42 has a pair of cable receiving grooves formed therein. The forward sheave 39 is ixedly secured to the forward shaft 32, the intermediate sheave 42 is mounted for free rotation on intermediate shaft 28, while the aft sheave 41 has a xed relation with respect to the supports 46 but is mounted for rotation on the shaft 33.

A continuous cable 43 extends between and is positioned in the groove formed in the aft sheave 41 and one of the grooves in the intermediate sheave 42 as shown in FIGURE 2, and is secured to each sheave at respective single points as indicated at C and D. Similarly a continuous cable 44 extends between and is positioned in the other groove formed in the intermediate sheave 39 and the groove formed in the sheave 39 and is secured to each sheave at single respective points as indicated at E and F.

The linkage assembly 14 is mounted in the enclosure 12 -to the aft wall 20, at a location substantially aft of the opening 23, by means of a pair of bracket supports 46--46. This mounting is effected by pivotally mounting the aft shaft 33 in the outer ends of the brackets 46-46. Also in the mounted position of the assembly 14 the aft sheave 41 is iixedly secured to one of the supports 46 and therefore is maintained in a fixed position throughout the operation of the linkage assembly 14.

The major sheave 34 is restricted to limited angular movement on the shaft 33 by means of a screw member 47 and hand wheel 4S. The screw member 47 is pivotally mounted in the aft wall 20 in a manner precluding longitudinal movement thereof while its threaded portion engages a nut 49 xedly secured to the sheave 34 at a predetermined radial distance from the center of the sheave. Thus it will be seen that the sheave 34 is normally retained in a fixed position on the shaft 33 but may be moved through a predetermined arc if required for a purpose to be described later.

The prime mover for the linkage assembly comprises a piston-type hydraulic actuator assembly 51. The cyllinder end of the actuator assembly 51 is pivotally attached to an arm 52 as best seen in FIGURE 2, the arm 52 is in turn lixedly secured to the sheave 34. The outer end of the piston rod of the assembly 51 is pivotally secured to a gusset-like plate 53 which is fixedly secured to and depends from the assembly 27. Pressurized fluid for the assembly 51 is provided by a pump and reservoir combination 54. Fluid flow may be selectively directed to either end of the cylinder of they assembly 51 by means of a valve 56.

A supply of electrical current for the heaters 40 located in the reflector 16 is provided by a supply line S7. Current for the aforementioned heaters flows through cables 58 extending between the supply line and the reflector 16. It will be noticed that the cables 58 are supported by and move with certain of the tubular elements comprising the assemblies 26 and 27 Referring to l IGURE 2, in which the linkage assembly 14 is shown in its centered extended position, it will be seen that the assembly 14 lies generally in a horizontal plane identified in the figure by the letter G. It will also be noted that the single attachment point of the cable 36 to the sheave 34, also the attachment points of the cables 43 and 44 to the sheaves 39, 41 and 42, is also located in the horizontal plane G.

'Having described the various components of the apparatus 11 a better understanding thereof, also the manner in which the apparatus functions, will be forthcoming from the following explanation of its operation.

It will be apparent that the linkage assembly 14 and the reiiector 16 may be raised or lowered from the centered extended position of FIGURE 2 by rotating the handwheei `S in a clockwise or counterclockwise direction. Rotational movement of the member 47, for example in a clockwise direction, will impart counterclockwise movement to the sheave 34; movement of the sheave 34 is in turn imparted to the sheave 31 through the cable 36 in a two to one (2:1) ratio due to the different diameters of the sheaves 34 and 31. During the above movement the common plane containing the heaters 40 in the reflector 16, also the top of the reflector 38, is maintained in a horizontal attitude by the cable linkage extending between the sheaves 39, 41 and 42. Inasmuch as the sheaves 39, 41 and 42 have the same diameters there will be no rel-ative angular movement between the fixed aft sheave 41 and the forward sheave 39 and, therefore, the reflecor 16 will be maintained in a horizontal attitude as the linkage assembly 14 is either raised or lowered as described above.

If pressurized fluid is now directed to the piston rod end of the assembly 51 the linkage assembly 14 is caused to assume its full retracted-position in which the assembly 14 and reflector 16 are located entirely within the enclosure 12 as shown in FIGURE 3. In moving between its extended and retracted positions as shown in FIG- URES 2 and 3, respectively, the move is initiated by the assembly 51 acting to move the subassembly 27 through approximately to the substantially vertical position of FIGURE 3. During this move, and due to the two to one (2:1) ratio between the diameters of sheaves 34 and 29, the subassembly-26 is rotated by the cable 36 through an angle of approximately Throughout this movement the reflector 16 is maintained in a horizontal attitude due to the coaction between the sheaves 39, 41 and 42 and the cables 43 and 44 for reasons previously explained.

In view of the foregoing explanation it will now be apparent that the linkage assembly 14 may be moved from its retracted to its extended position as described above and the reflector and common plane of the heater tubes 40 will at all times be maintained in a horizontal plane for reasons previously explained. It should also be noted that the outer portion of the assembly 14 and the reector 16 moves and extends through the opening 23 in moving between its extended and retracted positions.

t will now be apparent that the apparatus 11 may be positioned adjacent to a forming facility in which a titanium blank that is to be formed has previously been positioned. The linkage assembly 14 is moved to its extended position (FIGURE 2) in which the retlector is located directly above the titanium blank. The heaters in the reector 16 are now energized and the blank is heated to a predetermined temperature. As soon as the blank reaches the desired temperature the linkage assembly 14 is retracted (FIGURE 3) and the forming operation is effected. It requires only a fraction of a second to retract the assembly 14 and, therefore, a delay of only one or two seconds occurs between the time the blank reaches its v allowable maximum temperature and the actual forming operation.

While in order to comply with the statute, the invention has been described in language more or less specific as to structural features, it is to be understood that the invention is not limited to the specic features shown, but that the means and construction herein disclosed comprise a preferred form of putting the invention into effect, and the invention is therefore claimed in any of its forms or modications Within the legitimate and valid scope of the appended claims.

What is claimed is:

l. In apparatus facilitating the moving and positioning of a heat source, the combination comprising: a structure; a linkage assembly including elongated forward and aft portions pivotally connected at respective ends by an intermediate shaft allowing angular movement therebetween through a predetermined angular range; an aft shaft mounted in said structure; the other end of said aft portion being pivotally mounted on said aft shaft; a forward shaft pivotally mounted in the other end of said forward portion; a minor sheave of predetermined diameter pivotally mounted on said intermediate shaft and being tixedly secured to said forward portion for movement therewith; a major sheave of predetermined diameter pivotally mounted on said aft shaft; adjustable means mounted in said structure and contacting said major sheave whereby pivotal movement of the latter may be arrested at a plurality of angular positions on said aft shaft; means on said major and minor sheaves adapted to impart a predetermined angular movement to the latter sheave in response to relative angular movement between said forward and aft portions; means mounted on said fore, aft and intermediate shafts whereby the angular relation of said forward shaft is maintained with respect to a horizontal reference plane coincident with the axis of said forward shaft as said forward and aft portions are angularly moved through their predetermined ranges, means adapted to irnpart said angular movement occurring between said forward and aft portions.

2. I n apparatus facilitating the moving and positioning of a heat source as set forth in claim l: further characterized in that said adjustable means constitutes nut and screw means allowing the angular relation of said major sheave to be altered on said aft shaft with respect to a horizontal plane.

3. In apparatus facilitating the moving and positioning of a heat source as set forth in claim l: further characterized in that said means on said major and minor sheaves constitutes cable means secured at respective points to said major and minor sheaves.

4. In apparatus facilitating the moving and positioning of a heat source as set forth in claim l: further characterized in that said means mounted on said fore, aft and intermediate shafts constitutes fore, aft and intermediate sheaves of equal diameters mounted on said fore, aft and intermediate shafts, respectively, said aft and intermediate sheaves being mounted for rotational movement on their respective shafts; said aft sheave being secured to said structure to arrest rotational movement thereof; said forward sheaves being secured to said forward shaft for movement therewith; continuous cable means surrounding and secured to said aft and intermediate sheaves; and continuous cable means surrounding and secured to said intermediate and forward sheaves.

5. In apparatus facilitating the moving and positioning of a heat source, the combination comprising: a structure; a linkage assembly including elongated forward and aft portions pivotally connected at respective ends by an intermediate shaft allowing angular movement therebetween through a predetermined angular range; an aft shaft mounted in said structure; the other end of said aft portion being pivotally mounted on said aft shaft; a forward shaft pivotally mounted in the other end of said forward portion; a minor sheave of predetermined diameter pivotally mounted on said intermediate shaft and being tixedly secured to said forward portion for movement therewith; a major sheave of predetermined diameter pivotally mounted on said aft shaft; adjustable means mounted in said structure and contacting said major sheave adapted to arrest angular movement of said major sheave at a plurality of angular positions on said aft shaft; means on said major and minor sheaves adapted to impart a predetermined angular movement to the latter sheave in response to relative angular movement between said forward and aft portions; means mounted on said fore, aft and intermediate shafts adapted to maintain the angular relation of said forward shaft with respect to vertical and horizontal planes as said forward and aft portions are angularly moved through their predetermined ranges and means adapted to impart said angular movement occurring between said forward and aft portions.

References Cited in the file of this patent UNITED STATES PATENTS 1,347,695 Gillespie July 27, 1920 1,794,667 Blake Mar. 3, 1931 1,894,590 Ingersoll Jan. 17, 1933 1,978,417 Dreisonstok et al Oct. 30, 1934 2,197,430 Graves et al iApr. 16, 1940 2,278,607 Anderson Apr. 7, 1942 2,396,218 Watters Mar. 5, 1946 2,569,354 Tracy Sept. 25, 1951 2,582,358 Schoellerman Ian. 15, 1952 2,961,523 Hanson et al. Nov. 22, 1960 

1. IN APPARATUS FACILITATING THE MOVING AND POSITIONING OF A HEAT SOURCE, THE COMBINATION COMPRISING: A STRUCTURE; A LINKAGE ASSEMBLY INCLUDING ELONGATED FORWARD AND AFT PORTIONS PIVOTALLY CONNECTED AT RESPECTIVE ENDS BY AN INTERMEDIATE SHAFT ALLOWING ANGULAR MOVEMENT THEREBETWEEN THROUGH A PREDETERMINED ANGULAR RANGE; AN AFT SHAFT MOUNTED IN SAID STRUCTURE; THE OTHER END OF SAID AFT PORTION BEING PIVOTALLY MOUNTED ON SAID AFT SHAFT; A FORWARD SHAFT PIVOTALLY MOUNTED IN THE OTHER END OF SAID FORWARD PORTION; A MINOR SHEAVE OF PREDETERMINED DIAMETER PIVOTALLY MOUNTED ON SAID INTERMEDIATE SHAFT AND BEING FIXEDLY SECURED TO SAID FORWARD PORTION FOR MOVEMENT THEREWITH; A MAJOR SHEAVE OF PREDETERMINED DIAMETER PIVOTALLY MOUNTED ON SAID AFT SHAFT; ADJUSTABLE MEANS MOUNTED IN SAID STRUCTURE AND CONTACTING SAID MAJOR SHEAVE WHEREBY PIVOTAL MOVEMENT OF THE LATTER MAY BE ARRESTED AT A PLU- 